This artist's concept shows a recently discovered planet orbiting Alpha Centauri B, one of three stars in the Alpha Centauri system. Alpha Centauri is the closest star system to our own, at just 4.3 light-years. The planet is only a few million miles from the star, so its surface is sizzling hot, making it inhospitable to life. Even so, it is the closest known planet outside our own solar system. Alpha Centauri A, the brightest and most massive member of the star system, is at lower left. Our own Sun is the bright yellow star at upper right. [ESO/L. Calçada/Nick Risinger (skysurvey.org)]

Astronomers have been searching for a planet in the nearest star system for decades. And last year, their patience finally paid off: A team of European astronomers discovered an Earth-sized planet orbiting one of the three stars of Alpha Centauri.

Before you pack your bags, though, be forewarned that the new world is even hotter than Mercury, the closest planet to the Sun. It’s only a few million miles from its star, so its surface is heated to thousands of degrees - a world you would not really want to visit.

Alpha Centauri consists of three stars that travel through space as a family. Star “A” is similar to the Sun, star “B” is a little smaller and cooler than the Sun, and star “C” is a faint cosmic ember. The newly discovered planet orbits B.

Although the planet is hot and hostile, it’s possible that other worlds orbit the star at greater distances, where conditions could be much more comfortable - perhaps even in the habitable zone, where temperatures are just right for liquid water. And searches continue for planets around Alpha Centauri’s other two stars as well.

The Alpha Centauri system is just four-and-a-third light-years from Earth. As stars go, that’s just down the block. Yet it’s still 7,000 times farther than Pluto, which no spacecraft has yet reached. So even though the new world and any others that might inhabit the system are our closest planetary neighbors, it’ll still be a long time before we can pay them a call.